Author: Brian Benchoff

Ah, the autorouter. Inside every PCB design tool, there’s a function called the ‘autorouter’. This function, when used correctly, is able to automagically lay traces between pads, producing a perfect board in under a minute. The trouble is, no one uses it. We have been told not to trust the autorouters and we hear a lot of other dire warnings about it. The autorouter never works. The autorouter will put traces everywhere. The autorouter doesn’t consider floorplanning, and sometimes you’re going to get traces that go right through the edge of your board. Is avoiding the autorouter sound advice?

For this week’s Hack Chat, we’re talking about trusting the autorouter. The autorouter is just a tool, and like any tool, it will do exactly what you tell it. The problem, therefore, is being smart enough to use the autorouter.

Our guest for this week’s Hack Chat is Ben Jordan, Director of Community Tools and Content at Altium. Ben is a Computer Systems engineer, with 25 years experience in board-level hardware and embedded systems design. He picked up a soldering iron at 8, and wrote some assembly at 12. He’s also an expert at using an autorouter successfully.

In this Hack Chat, we’re going to talk to Ben about Altium, Circuit Maker, and how to get the best performance out of an autorouter. How do you set the autorouter up? How do you test your settings? What, actually, is the technology and math that goes into an autorouter? What is the best way to design a multilayer board? How do you do multiboard designs? And what’s the deal with mixed signals?

There’s a Starman, waiting in the sky. He’d like to come and meet us, but he’ll have to wait several million years until the Yarkovsky effect brings him around to Earth again.

In case you’ve been living under a rock for the past few weeks, SpaceX recently launched a car into space. This caused much consternation and hand-wringing, but we got some really cool pictures of side boosters landing simultaneously. The test launch for the Falcon Heavy successfully lobbed a Tesla Roadster into deep space with an orbit extending out into the asteroid belt. During the launch coverage, SpaceX said the car would orbit for Billions of years. This might not be true; a recent analysis of the random walk of cars revealed a significant probability of hitting Earth or Venus over the next Million years.

The analysis of the Tesla Roadster relies on the ephemerides provided by JPL’s Horizons database (2018-017A), and predicts the orbit over several hundred years. In the short term — a thousand years or so — there is little chance of a collision with anything. In 2091, however, the Tesla will find itself approaching Earth, and after that, the predicted orbits change drastically. As an aside, we should totally bring the Tesla back in 2091.

Even though the Tesla Roadster, its payload adapter, and the booster are inert objects floating in space right now, that doesn’t mean there aren’t forces acting on it. For small objects orbiting near the sun, the Yarkovsky effect is a huge influence on the orbit when measured on a timescale of millennia. In short, the Yarkovsky effect is a consequence of a spinning object being heated by the sun. As an object (a Tesla, or an asteroid) rotates, the side facing the sun heats up. As this side faces away from the sun, this heat is radiated out, imparting a tiny, tiny force. This force, over a period of millions of years, can send the Tesla into resonances with other planets, eventually sending it crashing into Earth, Venus, or the Sun.

The authors of this paper find there is a 6% chance the Tesla will collide with Earth and a 2.5% chance it will collide with Venus in the next one Million years. In three Million years, the probability of a collision with Earth is 11%. These are, according to the authors, extremely preliminary calculations and more observations are needed. If the Tesla were to hit the Earth, it’s doubtful whatever species populates the planet would notice; the mass of the Tesla is only 1250 Kg, and Earth flies through meteoroids weighing that much very frequently.

We got news this was going to happen last year, and now we finally have dates and a location. The East Coast RepRap Fest is happening June 22-24th in Bel Air, Maryland. What’s the East Coast RepRap Fest? Nobody knows; this is the first time it’s happening, and it’s not being produced by SeeMeCNC, the guys behind MRRF. There’s going to be a 3D printed Pinewood Derby, though, so that’s cool.

Intel hit with lawsuits over security flaws. Reuters reports Intel shareholders and customers had filed 32 class action lawsuits against the company because of Spectre and Meltdown bugs. Are we surprised by this? No, but here’s what’s interesting: the patches for Spectre and Meltdown cause a noticeable and quantifiable slowdown on systems. Electricity costs money, and companies (server farms, etc) can therefore put a precise dollar amount on what the Spectre and Meltdown patches cost them. Two of the lawsuits allege Intel and its officers violated securities laws by making statements or products that were false. There’s also the issue of Intel CEO Brian Krzanich selling shares after he knew about Meltdown, but before the details were made public. Luckily for Krzanich, the rule of law does not apply to the wealthy.

What does the Apollo Guidance Computer look like? If you think it has a bunch of glowey numbers and buttons, you’re wrong; that’s the DSKY — the user I/O device. The real AGC is basically just two 19″ racks. Still, the DSKY is very cool and a while back, we posted something about a DIY DSKY. Sure, it’s just 7-segment LEDs, but whatever. Now this project is a Kickstarter campaign. Seventy bucks gives you the STLs for the 3D printed parts, BOM, and a PCB. $250 is the base for the barebones kit.

A while back, [Marius] was faced with a problem. A friend of his lives in the middle of a rainforest, and a microphone was attacked by a dirty, greasy rat. The cable was gnawed in half, and with it went a vital means of communication with the outside world. The usual way of fixing a five- or six-conductor cable is with heat shrink, lineman’s splices, insulating tape, and luck. [Marius] needed something better than that, so he turned to his 3D printer and crafted his own wire splice enclosure.

The microphone in question is a fancy Jenal jobbie with a half-dozen or so conductors in the cable. A junction box was the obvious solution to this problem, and a few prototypes, ranging from rectangular to fancy oval boxes embossed with a logo were spat out on a 3D printer. These junction boxes have holes on either end, and when the cable ends are threaded through these holes, the wires can be spliced, soldered, and insulated from each other.

This microphone had to hold up to the rigors of the rainforest and rats, so [Marius] had to include some provisions for waterproofing. This came in the form of a hot glue gun; just fill the junction box with melted hot glue, pop the cover on, and just wait for it to cool. Like all good repairs, it works, and by the time this repair finally gives out, something else in the microphone is sure to go bad.

It’s a great repair, and an excellent example of how a 3D printer can make repairs easy, simple, cheap, and almost as good as the stock part. You can check out a few videos of the repair below.

If you buy a computer today, you’re probably going to end up with a laptop. Corporate drones have towers stuffed under their desks. The cool creative types have iMacs littering their open-plan offices. Look around on the online catalogs of any computer manufacturer, and you’ll see there are exactly three styles of computer: laptops, towers, and all-in-ones. A quick perusal of Newegg reveals an immense variety of towers; you can buy an ATX full tower, an ATX mid-tower, micro-ATX towers, and even Mini-ITX towers.

It wasn’t always this way. Nerds of a sufficient vintage will remember the desktop computer. This was, effectively, a tower tilted on its side. You could put your monitor on top, negating the need for a stack of textbooks bringing your desktop up to eye level. The ports, your CD drive, and even your fancy Zip drive were right there in front of you. Now, those days of desktop computers are long gone, and the desktop computer is relegated to history. What happened to the desktop computer, and why is a case specifically designed for a horizontal orientation so hard to find?

MIDI, the Musical Instrument Digital Interface, was released in 1983 in a truly bizarre association between musical instrument manufacturers. At no other time, before or since, has there been such cooperation between different manufacturers to define a standard. Since then, the MIDI spec has been expanded with SysEx messages, the ability to dump samples via MIDI, redefining the tuning of instruments via MIDI to support non-Western music, and somewhere deep in the spec, karaoke machines.

Now there’s a new update to the MIDI spec (Gearnews link, here’s the official midi.org announcement but their website requires registration and is a hot garbage fire). At this year’s NAMM, the place where MIDI was first demonstrated decades ago, the MIDI Manufacturers Association announced an update to MIDI that makes instruments and controllers smarter, and almost self-learning.

There are three new bits to the new update to the MIDI spec. The first is Profile Configuration, a way to auto-configure complex controller mappings, described as, ‘MIDI Learn on steroids’. The second update is Property Exchange, and allows MIDI devices to set device properties like, ‘product name, configuration settings, controller names, and patch data’. This is effectively setting metadata in controllers and devices. The third new bit is Protocol Negotiation, a way to automatically push future, next-gen protocols over a DIN-5 connector.

What does this all mean? Drones. No, I’m serious. The MIDI association is tinkering around with some Tiny Whoops and Phantoms, and posted a video of drones being controlled by a MIDI controller. Play a glissando up, and the drone goes up. You can check out a video of that below.

Some time before experimenting with MRI machines and building his own CT scanner, [Peter Jansen] wanted to visualize magnetic fields. One of his small side projects is building tricoders — pocket sensor suites that image everything — and after playing around with the magnetometer function on his Roddenberry-endorsed tool, he decided he had to have a way to visualize magnetic fields. After some work, he has the tools to do it at thousands of frames per second. It’s a video camera for magnetic fields, pushing the boundaries of both magnetic imaging technology and the definition of the word ‘camera’.

When we last looked at [Peter]’s Hall effect camera, the device worked, but it wasn’t necessarily complete. The original design used I2C I/O multiplexers for addressing each individual ‘pixel’ of the Hall effect array, limiting the ‘framerate’ of the ‘camera’ to somewhere around 30 Hz. While this would work for visualizing static magnetic fields, the more interesting magnetic fields around us are oscillating — think motors and transformers and such. A much faster magnetic camera was needed, and that’s what [Peter] set out to build.

Instead of an I/O expander, [Peter] re-engineered his design to use analog multiplexers and a binary counter to cycle through each pixel, one at a time. Basically, the new circuit uses two analog muxes for the columns and rows of the Hall effect array, a binary counter to cycle through each pixel at Megahertz speed, and a fast ADC to read each value. It is, bizarrely, the 1970s way of doing things; these are simple chips, and the controller (a Chipkit Max32) only needs to read a single analog value and clock the binary counter really fast.

With the new design, [Peter] is able to get extremely fast frame rates of about 2,000 Hz. That’s fast enough for some beautiful visualizations of spinning motors and transformers, seen in the video below. Further improvements may include three-axis magnetometers, which should allow for some spectacular visualizations similar to [Ted Yapo]’s 3D magnetic field scanner.